This invention relates to a dose rate meter intended for providing reliable and accurate measurements of ionization radiation dose rates in cases of nuclear emergencies such as reactor accidents, spillages of radio-active materials or a nuclear war. This instrument is intended for civil defense use and accordingly it must be capable of being stored for many years without servicing and must be available and operable instantly in cases of sudden need. Also, devices of this type should be easy to operate since most of them will be used by unskilled personnel often under the emotional stress of a real or imagined nuclear disaster.
The operation of this dose rate meter does not depend on any external power sources which would not be reliable in emergencies nor on batteries which have limited shelf life and hence require periodic replacement. The other components must be simple, durable and be unaffected by prolonged storage.
The dose rate range of this instrument is extremely wide, extending from background rates (or approximately 0.01 millirads/hr.) to 10,000 rads/hr. The high sensitivity capability is important for civil defense applications to let the user know that no radiation danger is present. In the case of an accident, for example a chemical explosion in the vicinity of a nuclear reactor, the suspicion that nuclear radiation may be present could cause panic. This instrument can be used in such a situation to put these fears to rest.
The meter of the present invention has a sampling and recording capability. This means that it can measure and preserve the reading of an ambient radiation dose rate, and the dose rate can be later read, for example in the safety of a shelter. The meter can provide successive samplings within short time intervals.